Electrical protective system



INVENToR y L, ZC Sway/t BY ATTORNEY May 12, 1936. L, K. swAR-r ELECTRICAL PROTECTIVE SYSTEM Filed March 14, 1935 Patented May 12, 1936 UNITED STATES PATENT OFFICE ELECTRICAL PROTECTIVE SYSTEM Leland Kasson Swart, Mountain Lakes, N. J., as-

signor to American Telephone and Telegraph Company, a corporation of New York Application Marchl 14,

6 Claims.

of said circuits and to provide for the testing of the protective apparatus.

Protector blocks each having two electrodes spaced by an air gap which breaks down at a predetermined potential are used at present in the telephone art for the protection of telephone circuits from high voltages set up therein by one or more sources extraneous to the circuits themselves; In these arrangements, a resistor or reactor is interposed in the ground connection of each pair of these protector blocks or in the common ground connection of all of the protector blocks. This resistor or reactor carries all the operating current of the blocks.

At present, low voltage protector blocks as com` monly used have an operating range around 350 peak volts. To provide operation of the protective devices at a xed predetermined value of po` tential, a gas discharge device with a multiplicity of actuating electrodes may be shuntedI around the protector blocks and, according to this invention, operation of the protective relay equipment may be obtained at a fixed operating voltage depending upon the design of the tube. This voltage can be made to lie above the normal operating voltages applied to the conductors and below the minimum of the protector blocks.

Gas tube devices can be designed to operate at a particular potential. Hence the operating potential of the protective equipment of this invention which involves such devices, will remain* constant within a few per cent. for all ordinary temperatures, etc. f

In accordance with this invention potential may be applied at a remote point for the purpose of operating the relay protective equipment and thus provide methods of testing this equipment Whenever desired. i

This .invention and the principles underlying it, some of which have been described hereinabove, will be better understood from the description hereinafter following when read in connection with the accompanying drawing inY which Figure 1 represents one embodiment of the invention and Fig. 2 represents a modication of some of the apparatus shown in Fig. 1.

In Fig. 1 reference characters W1 to W10, inclusive, represent ten of a. multiplicity of conductors. Each of these conductors may be connected to yground through an individual protector block 1935, Serial No. 11,176

as shown and a common reactor T, this reactor being shown as a winding wound about a. core, which may be of iron or alloys of iron and of the saturating type. The various protector blocks are designated P1 to P10, inclusive. The lower terminal of each of these blocks is connected to upper terminal of the primary wlnding of the transformer or reactor T and the upper terminal of each of said protector blocks is V connected to one of the corresponding conductors W1 to W10, respectively. Each of the various protector blocks may include two carbon electrodes spaced from each other by a gap of predetermined width.

The secondary winding of the transformer T is connected to one of the windings of thealternating current relay R1. The armatures and contacts of relays designated R10, R20, R30, R40 and R50 are associated with the protector blocks P1 to P10, the windings of all of these relays being connected in parallel, or in series parallel, in series with the batteri7 B and the armature and contact of the relay R1. When the relay R1 becomes operated, current will ilow from the battery B1 over the armature and contact of the relay R1 and through the windings of relays R10 to R50, inclusive. The heavy duty contacts of tnese relays provide paths in shunt with the various protector blocks P1 to P10 and thus pass current from the conductors W1 to W10, inclusive, through the primary winding of the transformer T to ground.

Each of the line conductors W1 to W10, inclusive, is connected to one of the electrodes G1 to G10, respectively, of the gas tube N. These lelectrodes may be of any size and configuration and mayor may not be. coated with activated material. LA large electrode or cathode K is enclosed within the tube N and this is connected to the upper terminal of the primary winding of the transformer T. This cathode K is also connected to the negative terminal of a battery B2 and to the Contact I4 of a relay R2 and to one side of the' condenser C. Also, there is an electrode A within the tube N which is connected to terminal l of the winding of the relay R2. Terminal 2 of the winding of relay Rzis connected to the armature I3 of said relay and to the upper terminal of winding 2 (or lower winding) of the'relay R1.

'I'he latter terminal of the winding of relayfR1 is also connected to the positive battery B2.

The operation of the short-circuiting relays R10 to R50 inclusive,'not only short-circuits the protectorblocks P1 to P10 inclusive, but aiso shortterminal of the yso 2 .V circuits the electrodes G1 to G10, and the cathode K oi' the tube N. This is discernible from the factl that one of the armatures ofeach of the relays R10 to Rw and its contact. shunts one of the electrodes G1 to G10 and the cathode K.

The relay R2 and condenserC and resistance R perform the functions required in restoring the gas tube N to normal as well as applying a holding current to the winding 2 of the relay R1 during the interval of time in which the relay R2 is operated. The operation of the device is as follows: Potentials of either polarity or alternatingv potentials may be impressed between any of the conductors W1 to Win and ground by power induction or lightning or any Aother extraneous .source to which the lines may be exposed. When any suchpotential reaches a value in excess of that required to cause discharge between any one of the electrodes G1 to G1o,.inclusive, to the cathode K, current will immediately rlow from battery B2 through the winding 2 of relay R1, the winding-of relay Rz and from the anode'A to the cathode K through the ionized gas of the tube N.

Operation of the relay R1 immediately. takes place, causing the operation of all ofthe shortclrcuiting relays Rin to Rao. inclusive, thereby 'shunting all of the protector blocks P1 to P10, in-

cluslve. Electrodes G1 to G10. inclusive, being connected to the various protector blocks P1 `to P10, respectively, also become shunted, to the cath-` jode K o1' the gas tube N by-virtue of the simultaneous operation of all said short-circuiting reclose contact Il.

rent from battery Bz to the winding 2' of the relay lays R10 to Bm.

' 'I'he current passing 'from the anode A to the cathode K as above described also produces oper.

ation of the relay R1 causing its armature I3 to This will supply .additional cur- R1 and thereby maintain relay R1 operated as long as relay Rz' remains operated. The closure of 'contact I4 by armature I3 or relay Rz will withdraw the potential of battery Bz' from the tainingv value of the glow between those elements winding ofrelay Rz and the anode A of the gas tube N. The withdrawal of the potential from' the winding of relay R.: causes the latter relay to restore to the non-operated condition and the armature I l willleave contact I4' unless the potentialapplied tolanyone of the velectrodes G1 to' Gin and cathode K exceeds that required to maintain the gas within tube N ionized.

When armature I3 leaves contact Il, the condenser C becomes charged by battery Bq through winding 2 of relay R1. Withdrawal oi.'I potentiall from relay Rz by armature I3 and contact `II, also reduces the potential -between the anode A and the cathode K to a value less than the susandthus deionizes the gas within the tube N.

The short-circuiting of the electrodesG1 to ChoA to the cathode K by the armatures and contacts of relays Rio to Rm, inclusive, deionizes the gas Ibetween the electrodes G1 and Gm andthe cathprimary winding of transformer T. 'By virtue4 of tho'connection of the secondary winding of transformerT to winding I' (the upper winding) of relay R1, Vthe latter 'relay willbe heldin the. operated position for the duration of the 4applied potential to anyone of the conductors W1 to Win. Withdrawal of potential from the various conductors W1 to W10 restores relay R1 to itsnormal, unoperated position and the latter relay will restore relays R10 to, R50, inclusive, to their nor'- malrand unoperated positions. The relay Rz' 'also restores to 'normal the instant that electrodes GrtoGio inclusive,-become short-circulted to the cathode K. Other and varied arrangements for restoring the gas tube to normal will occur to those skilled in this art. and they may be used if desired.V

` The relayV R1 may be of the multi-contact type performing all the functions of the short-circuiting relays R10 to R511, as is well known, and if such a relay is employed, the battery B1 will not beI required.' Moreover, the transformer T may be replaced by a multi-contact type of relay. This relay should then, therefore', be one of the saturating type. 'I 'his relay may be `arranged to perform the functions of all of the various shortcircuiting relays, as is well known.

The operation of relay R1 may occur when any one or several or all of the protector blocks P1 to P1ohave broken downor when the gas between any one or several or all of the electrodes G1 to Gm of tube N and its cathode K has become ionized. The ionization voltage may be below the breakdown voltages of all of the protector blocks or it may be' below the generalaverage of their breakdown voltage values. The tube N.is designed sothat its ionization voltage will be higher than the normal operating voltages applied to any or 'all of the conductors W1 t0 W10.

In the arrangement shown in Fig. 1, a resistor may be substituted for-the transformer T. Moreover, an auto-transformer or a simple saturating'4 reactor may take the place ofthe transformer T, as is well known.

Fig. 2 shows an alternate arrangement for carrying out the principles of this invention.

The alternating current relay R11 includes two'` the' winding of short-circuiting relay Roo which -may be of the multi-contact type, if desired, for simultaneously shunting all `of the protector blocks. -The battery B1 and the armature and contact of relay R11 may be connected in series with each other and in shunt with the windings of relays R1 and Rao, as'shown. In this arrangement, relays Re and R40 will both always be operated or unoperated, although it will be understood that relay Rz may be o1' the high speed or vibratory type, if desired. y 3

While this invention has been shown and described in certainparticular arrangements mere- Aly for the purpose of illustration, it will be understood that the general principles of this inven- 'tion may be applied to other and widely varied 1. Apparatus for the protection of a plurality of conductors comprising a gas-nlled tube havinvention and the scope of the appendedV ing an anode, a cathode, and a plurality of electrodes each of which is connected to`one of the conductors, means responsive to a voltage exceeding a predetermined value applied to any one of the various conductors to ionize 'the gas between the anode and cathode of said tube, and

' means responsive to the ionization of the gas within said tube to simultaneously ground all of said conductors.

2. Apparatus for the protection of a plurality of circuits, comprising a plurality of protector blocks one terminal of which is connected to one of the circuits, a saturating transformer the primary of which is connected between the other terminal of each of the protector blocks and ground,- a gas-filled tube including an anode, a cathode and a plurality'of electrodes each of which is connected to one of the circuits, the cathode of the tube being connected to the conductor common to all of the protector blocks, a ilrst relay having two windings, one of which is connected to the secondary winding of the transformer, a second relay, and a source of potential which is connected in series with the second winding of the rst relay, the winding of the second relay and the anode and cathode of the tube, the armature and contact of the second relay being connected in series with the winding of the latter relay and the anode and cathode of the tube, and means responsive to the operation of the first relay for simultaneously grounding all of the circuits.

A 3. Apparatus for the protection offa plurality p of conductors, comprising means for simultaneo`usly grounding all of the conductors when the potential applied to any one 'of the said con^ ductors exceeds a predetermined value, said. means comprisinga gas-filled tube having a cathode and a plurality of electrodes. each of which is connected to one of the conductors, the cathode of said tube being connected to ground.

4. Apparatus for the protection of a plurality of conductors, comprising a plurality of protector blocks one terminal of each of which is connected to one of the conductors, a reactor connected between the other terminal of each of the protector blocks and ground, a gas-nlled tube including a cathode and a plurality oi electrodes each of which is connected to one of the conductors, the cathode of the tube being connected to the ungrounded terminal of the reactor, and means responsive to the application of a predetermined voltage to the reactor for simultaneously connecting all of the conductors to ground through said reactor.

I 5. Apparatus for the protection oi a plurality of conductors, comprising a reactor one terminal of which is grounded, a gas-filled tube lncluding an anode, a lcathode and a plurality of electrodes each of which is connected to one of the conductors, the cathode being connected to the ungrounded terminal of the reactor, a relay, a source of potential connected in series with the winding of the relay and the anode and cathode of the tube, and means responsive to the operation of said relay for simultaneously grounding all oi' the conductors through a circuit including said reactor and independent paths provided by each of the electrodes of said tube and its cathode.,I

6. Apparatus for the protection of a plurality of conductors comprising a plurality of protector blocks one terminal of each of which is connected to one of the conductors, a reactor one terminal Aof which is connected to the other terminal of each of the protector blocks, the other terminal of the reactor being grounded, a relay the winding o1' vwhich is connected to said reactonmeans responsive to the operation of said relay for simultaneously grounding all ol! vthe conductors through said reactor, a gas-nlled tube including an anode, a cathode and aplurality of electrodes each of which is connected to one oi the conductors, the cathode being connected to the ungrounded terminal of the reactor, and means responsive to the ionization of the gas between the anode and cathode of said tube for operating said relay.

`KASSO SWART. 

